000
FGUS71 KBUF 151128
ESFBUF
NYC003-009-011-013-029-037-045-049-051-055-063-069-073-075-117-
121-200400-
Winter/Spring Flood Potential Outlook
National Weather Service Buffalo NY
730 AM EDT Thu Mar 15 2018
...NEAR NORMAL FLOOD RISK THROUGH MARCH 29TH...
This is the sixth flood potential outlook of the 2018 season. Flood
outlooks will be issued every two weeks into early spring to
summarize basin conditions and to assess the potential for flooding.
The outlooks are based on current and forecast hydrometeorological
conditions. This includes snow cover and water equivalent, creek and
river levels and the amount of ice on them, along with the expected
conditions during the next two weeks.
...CURRENT CONDITIONS SUMMARY...
A warm up going into the month melted nearly all of the snow pack in
the Buffalo Creeks and the Genesee and Allegheny River basins. Since
then, a very snowy pattern has developed which has re-established a
snow pack across the region. Snow water equivalent values (SWE) are
mainly in the 1-2 inch range in these basins with higher amounts
across higher terrain, and especially across the Tug Hill Region.
This is above normal SWE for this mid-March.
Snow pack was not completely melted in the Black River basin, with
significant amounts of snow confined to higher terrain including the
Tug Hill plateau and western Adirondacks. Recent snows have re-
established snow pack across lower terrain, and added to an existing
snow pack across higher terrain. As a result SWE is variable in the
basin, but generally is near to a bit above normal for mid-March.
Although it has been a snowy pattern with temperatures slightly above
normal, nights have not been that cold and the higher March sun
angle has helped limit ice from reforming on creeks and rivers.
There is some patchy shore ice, but not thick enough to cause
significant ice jam issues.
The following is a summary of the conditions by basin as of early
Thursday morning, March 15th:
...BUFFALO AREA CREEKS / LAKE ERIE BASIN...
.SNOW COVER..........6 to 12 inches, up to 18 across higher terrain.
.WATER EQUIVALENT....1-2 inches, up to 3 across higher terrain.
.CREEK FLOWS.........Below normal.
.CREEK ICE...........Patchy shore ice.
.GROUND FROST........Less than 6 inches where frozen.
.GROUND STATE........Variable, partially frozen or saturated.
...GENESEE RIVER BASIN / FINGER LAKES / ROCHESTER AREA...
.SNOW COVER..........4 to 12 inches.
.WATER EQUIVALENT....Mainly 1-2 inches, a bit less in some valleys.
.RIVER/CREEK FLOWS...Below normal.
.RIVER/CREEK ICE.....None.
.GROUND FROST........Less than 6 inches where frozen.
.GROUND STATE........Variable, partially frozen or saturated.
...ALLEGHENY RIVER BASIN...
.SNOW COVER..........10 to 20 inches.
.WATER EQUIVALENT....Around 2 inches.
.RIVER/CREEK FLOWS...Below normal.
.RIVER CREEK ICE.....None.
.GROUND FROST........Less than 6 inches where frozen.
.GROUND STATE........Variable, partially frozen or saturated.
...BLACK RIVER BASINS / TUG HILL...
.SNOW COVER..........6 to 18 inches, except 2-3 feet on the Tug Hill
and Adirondacks.
.WATER EQUIVALENT....1-3 inches, except 4 to 10 inches on the Tug
Hill and Adirondacks.
.RIVER/CREEK FLOWS...Near normal.
.RIVER/CREEK ICE.....Mainly open, some shore ice.
.GROUND FROST........Mainly frozen, less than 6 inches.
.GROUND STATE........Mainly frozen.
...TEMPERATURE AND PRECIPITATION OUTLOOK...
Temperatures are likely to remain below normal for the next two
weeks. Model guidance suggests an upper level low will remain across
eastern Canada through the end of next week. This would maintain a
generally cool northwesterly flow aloft with daytime highs in the
30s and 40s. There will be chances for precipitation in this pattern,
but this will more likely than not fall as snow.
Later in the outlook period, there is both increasing uncertainty
and also a hint of a slightly warmer pattern. If there is a warm up
with rain, it would likely be toward the end of March. The 8 to 14
day outlook is for below normal temperatures and above normal
precipitation.
...FLOOD POTENTIAL OUTLOOK...
The flood risk for the next two weeks is near normal.
An above normal snow pack is offset by a pattern which will
generally not be conducive to cause widespread flooding. The pattern
should remain cold through at least the first week of the outlook
period with precipitation likely to fall as snow. Despite below
normal temperatures, expect that snow on the ground will gradually
diminish but quickly enough to cause any issues.
There is some risk of a warm up later in the outlook period, and if
this does occur it would increase the risk for flooding which
justifies the normal risk. However, it is also quite possible that
the pattern will remain cold all the way through the end of the
month.
...ADDITIONAL INFORMATION...
Real time river information and probabilistic forecast for
specific locations along rivers across Western New York can be
found on the internet at www.weather.gov/buf. Since conditions can
change, please refer to the latest flood watches, warnings, and
statements for additional information.
Thank you to all the observers and agencies which have helped
gather data in support of this outlook. The next Winter/Spring
Flood Outlook will be issued on March 29th.
$$